Human Eye And Colourful World Test - 2

Large dust particles and the water droplets present in the clouds scatter all the wavelengths almost equally. Hence, clouds appear white.

Angle of minimum deviation is directly proportional to refractive index. Refractive index for red is least while for violet is maximum. Refractive index is inversely proportional to the wavelength of the light. As red has a higher wavelength than violet light, it has a smaller refractive index than violet.

Power, P = – 2 D
Or f = 1/P = -0.5 m
This is the case of myopic eye, where the person is suffering from short sightedness and the far point is less than infinity. We need far point after which vision is not possible and where the image of an object kept at infinity has to be formed.
u = – ∞ (infinity)
v = ?
f = – 0.5 cm
1/f = 1/v - 1/u (Lens formula)
Or 1/v + 0 = - 1/0.5 or v = - 0.5 m = - 50 cm
The distance beyond which he is not able to see the objects clearly is 50 cm.

The blind spot refers to the area, where both rod cells and cone cells are absent. Because there are no cells to detect light on the optic disc, the corresponding part of the field of vision is invisible.

One cannot see through fog because light is scattered by the droplets in the fog.
Scattering of light is the phenomenon in which when light passes from one medium to any other like glass, water, or air, then a part of the light is absorbed by particles of the medium preceded by its subsequent radiation in a particular direction.

Refraction is the phenomenon which makes image formation possible by the eyes. Our eyes comprise of convex lens, which is a converging lens. When parallel rays of light pass through a convex lens, the refracted rays converge at one point called the principal focus.